The proposed project seeks to understand healthy aging processes through an investigation of cognition in context. In accord with the mission statement of the Behavioral and Social Research (BSR) program of the NIA, the long-term objective of the proposed research is to identify how social contexts shape cognitive development. Of specific interest is how individuals draw from their own abilities and interpersonal relationships to solve problems of daily life and age successfully. The objective of this project, which is one step toward understanding how social contexts shape cognition, is to compare the consequences of working alone versus collaborating with a familiar social partner for younger and older adults' solutions to interpersonal and instrumental everyday problems. Thus, the project addresses cognition in the context of social relationships in daily life. Specifically, the aims of the proposed research are to: (a) compare the performance of younger and older adults who interact with a partner or work alone to solve instrumental and interpersonal everyday problems, and (b) determine how interpersonal, cognitive, and motivational processes that occur during collaborative interactions facilitate or hinder problem-solving performance in early and later adulthood. The central hypothesis of the research is that younger and older adults' problem-solving performance (as indexed by the quality and quantity of their strategies for solving ill-defined instrumental and interpersonal problems) will vary systematically as a function of working with a partner versus working alone, the instrumental or interpersonal domain of the problem, partners' cognitive abilities and motivation for working together, and the perceived quality of face-to-face social interaction. This central hypothesis is tested systematically and comprehensively in order to provide concrete knowledge of the gains and losses that may accrue when younger and older adults collaborate with others to solve everyday problems. Without this knowledge, associations between social relationships and cognitive performance in later life will remain underdeveloped. By providing this knowledge, the proposed research will facilitate the development of empirically-supported interventions to improve individuals' skills for solving everyday problems and make significant theoretical and empirical contributions to the research literature.